World’s biggest antimatter nucleus produced at Brookhaven

Scientists at the Relativistic Heavy Ion Collider have spotted an antimatter …

Roughly a year ago, a paper came out describing some very strange atomic nuclei that had been produced at the Relativistic Heavy Ion Collider, based at Brookhaven National Lab on Long Island. These atomic nuclei were not only comprised of antimatter, but some of their components incorporated strange quarks, instead of the usual up and down versions. The RHIC is back in the news today, as one of its detectors has found evidence of the production of anti-helium-4 nuclei. The rates at which these particles were produced, however, suggests that we won't be seeing anti-nuclei of any greater complexity anytime soon.

4He, also known as an alpha particle, is comprised of two protons and two neutrons, or four baryons in total. Antimatter versions of 3He were first detected decades ago, but the anti-alpha has been harder to identify. They're hard to spot in a particle collider simply because of the process by which they're formed. "A light nucleus emerging from a relativistic heavy-ion collision is produced during the last stage of the collision process," the authors state. "The quantum wavefunctions of the constituent nucleons, if close enough in momentum and coordinate space, will overlap to produce the nucleus."

It's that proximity of both location and energy that makes forming an antimatter version so unlikely. You have to have the right number of antimatter baryons of the right types traveling near each other for a nucleus to condense. The more baryons involved, the lower the probability. RHIC ups the odds of this happening by colliding two gold atoms, which bring a lot of baryons together in a very compact space.

To spot anti-alphas, RHIC's STAR detector team used a filter that selected only head-on collisions (which rejected about 90 percent of the data), leaving 109 collisions from 2010 to work with. Those were filtered for particles that traveled as if they had the appropriate charge and a heavy mass—this required real-time reconstructions of particle trajectories from these collisions, which is an impressive computational feat.

Plotting the particles according to their behavior revealed heavy bands corresponding to 3H and 3He, and a thin band beyond them that corresponded to (depending on the charge) regular and antimatter alpha particles. The production rate apparently agreed nicely with theoretical values.

Both the RHIC and the Large Hadron Collider (which spends part of its time colliding heavy lead atoms), are sometimes referred to as "mini Big Bang machines," because the soup of quarks and gluons they create were last seen during the Big Bang. But the colliders are actually better at producing complex antiparticles than the Big Bang was, since the collisions evaporate off into empty space—the Universe's density immediately after the Big Bang was so high, the antiparticles wouldn't go far without running into something else.

Unfortunately, the theories that the RHIC data support indicate that the LHC's collisions won't be sufficient to produce any anti-nuclei with higher numbers of baryons, like an anti-lithium. The authors do note that, should the LHC produce some, then we'd be spotting some really unexpected physics: "A deviation from the usual rate reduction with increasing mass would be an indication of a radically new production mechanism."

But the results could help provide a new perspective on astronomy. We're just now planning to put hardware into space that could detect an anti-alpha. Given the RHIC results and a clear indication of how much anti-4He is out there, we should get a measure of the amount of antimatter present in the cosmos.

So exactly how sure are these folks that their anti-matter experiments won't vaporize the whole universe? Not that anyone would be around to blame them if they did.

Although this is not my field of study, my understanding is that an amount of anti-matter will react with an equal amount of matter and release energy. With our current level of tech, you don't have to worry about a mad scientist destroying the earth on purpose or a sane scientist doing it on accident.

To close, Dr. Xu made an overly confident prediction: while currently the heaviest known antimatter particle is the aforementioned anti-3ΛH, he expects that the discovery of a complete anti-α particle will be made in 2011. His demeanor led me to speculate that his team has a strong candidate for an anti-α particle, but that it has not yet been confirmed to a level that makes it ready for public release. Keep an eye on Nobel Intent to see if this prediction holds true.

There's an easy way to control the anti-alpha particles . . . dilithium silly! Just common sense.

Bravo to Brookhaven. Come to think of it, most major US high-energy research facilities are located near progressive, liberal cities: Brookhaven, NYC; Fermilab, Chicago; Lawrence Livermore, San Francisco; Los Alamos and Sandia, Albuquerque. Fermilab's successor, the Super-Conducting Super-Collider, was slated for Texas near Dallas which is the same place that gave this country the GW Bush slant on science.

So exactly how sure are these folks that their anti-matter experiments won't vaporize the whole universe? Not that anyone would be around to blame them if they did.

I'm no nuclear physicist, buuuuuut... the matter -> energy conversion of multiple kilograms of nuclear material is needed to make those neat mushroom clouds. These experiments are only making a few atoms. So not even a mad scientist could intentionally blow up the earth. I'd be first in line.

Quote:

Unfortunately, the theories that the RHIC data support indicate that the LHC's collisions won't be sufficient to produce any anti-nuclei with higher numbers of baryons, like an anti-lithium.

You know, I'm hearing more stories about other collider facilities than CERN lately. What is the LHC up to, considering it's supposed to be the biggest and best?

Well, the RHIC is the LHC's cousin . They test out the LHC upgrades at the rhic first . If you go to the rhic website at brookhaven they explain this. Also if you want proof put in electron lenses and lhc into google.

Also brookhaven is a big partner in the lhc. (they helped build the lhc and help run atlas ) so they tend to share a lot of the data between the two colliders. The rhic collides heavy ions ALL the time while the lhc only collides them part of the time. Thats another reason why the rhic might have found this first.

Keep in mind the lhc isnt the best at everything. It does not do spin polarized protons like the rhic can and the rhic is going to test using uranium ions instead of gold or lead.

PS anybody who lives in the NY area and likes science like this should really visit the family sundays at brookhaven. They give tours of the rhic and its detectors. they actually bring you to the detecors themselves and bring you as close as the pic in this article. Also some of the rhic scientists colaborate and have worked on the lhc so you can have some cool conversations with them .

There's an easy way to control the anti-alpha particles . . . dilithium silly! Just common sense.

Bravo to Brookhaven. Come to think of it, most major US high-energy research facilities are located near progressive, liberal cities: Brookhaven, NYC; Fermilab, Chicago; Lawrence Livermore, San Francisco; Los Alamos and Sandia, Albuquerque. Fermilab's successor, the Super-Conducting Super-Collider, was slated for Texas near Dallas which is the same place that gave this country the GW Bush slant on science.

NYC may be home to progressives, liberals and democrats but BNC in Upton is home to mostly conservatives and tea partiers.

This is a huge risk. What if the create a mini blackhole? Maybe we should not play with such toys when we are not guaranteed the outcome.

Look what happened thanks to those physicists playing with radiation, we ended up with nuclear weapons.

please be sarcasm please be sarcasm.

In case it isn't, or for the benefit of those who I've posted such things in earnest, perhaps you have heard of some of the other outcomes of playing with radiation?Such as, X-ray machines, cancer treatments, and radioisotope dating.

So Ok you don’t buy that. Even if a black hole of such a size was created, it would evaporate.

So let’s try another approach, this test has already been done. No theory, no guessing, just a little belief that someone else says what he sees.

For a long as the Earth has existed, we have been bombarded with particles with even more energy that any lab made by mere man.

These particles, the ghosts of quasars, black hole formation and super nova hit the earth regularly. Occasionally, a very energetic particle hits the Earth. A particle at 3e20 eV (50 Joules) has been measured. In contrast, RHIC this year will starting at 2.5e11 eV (4e-8 Joules) and move up some from there. So if the cosmos has not created a black hole here on Earth, RHIC or LHC will not be creating a black hole.

As a side note if a 1 kg of matter was consumed in the nuclear explosion that would be a 21.5 Megaton explosion. The largest manmade nuclear explosion was 57 MT (2.6 kg), most have been less than 1 MT (46 g). For example a typical test yield of a 20 kT weapon would consume (0.9 g).

...perhaps you have heard of some of the other outcomes of playing with radiation?Such as, X-ray machines, cancer treatments, and radioisotope dating.

This really addresses a more serious problem in the world today. I've looked and there isn't one online dating site that caters to radioisotopes! I mean what's up with that? Why are we overlooking such a huge demographic? Especially since us playing with radiation is kinda responsible for that anyway... ;)

I take issue with the idea that the soup of particles created by these colliders was last seen during the Big Bang. First, who saw them during the Big Bang? No one had particle detectors yet. Second, doesn't it seem extremely likely that some alien race has at some point in the past built a particle collider capable of creating similar soups?

"I'm no nuclear physicist, buuuuuut... the matter -> energy conversion of multiple kilograms of nuclear material is needed to make those neat mushroom clouds. These experiments are only making a few atoms. So not even a mad scientist could intentionally blow up the earth. I'd be first in line. ;)"

what if ... speaking of mad scientists ... we going to feed that black hole with more matter. Take some stuff like pencils/pens and printer paper, whatever around the office (oh paper clips would work the best I think) and just trow them all in there ... won't it make the black hole bigger? :)

"I'm no nuclear physicist, buuuuuut... the matter -> energy conversion of multiple kilograms of nuclear material is needed to make those neat mushroom clouds. These experiments are only making a few atoms. So not even a mad scientist could intentionally blow up the earth. I'd be first in line. "

what if ... speaking of mad scientists ... we going to feed that black hole with more matter. Take some stuff like pencils/pens and printer paper, whatever around the office (oh paper clips would work the best I think) and just trow them all in there ... won't it make the black hole bigger?

Just curious ... Why can't it feed on itself?

At the same time, it is also (believed to be) evaporating due to Hawking radiation. Unless you "feed" it more than it evaporates in a certain amount of time, it will fizzle out. It is also known that the smaller the black hole, the faster it will evaporate. The "micro-black holes" that people say may be formed under these conditions basically evaporate to nothing very quickly and can't do much else.